In the late 1987 model year, Nissan changed the design of the VG30 engine, slightly, to provide a decrease in noise levels and an increase in power output. There is a lot of confusion as to what changes were actually made. This is a comprehensive listing of changes that were made to the VG30 engine.

Changes to the VG30 Engine (to create the W-series engine):
1987 Nissan-Datsun 300ZX V6-2960cc 3.0L SOHC MFI (VG30E)
Top - Vehicle
Engine
. Technical Service Bulletins
. . All Technical Service Bulletins
. . . VG30 Engine Modifications

VG30 Engine Modifications

VG30 ENGINE MODIFICATIONS:
Beginning with April, 1987 production, several major components of the VG30 engine have been changed to decrease noise levels and improve power output.

The MODIFIED AND NON-MODIFIED engines can be identified by the engine serial number as follows:

The major engine components that have been changed to create the “W” engine are shown below. In addition, a summary of changes is provided for each component.

Six new water galleries were added at the exhaust side of the cylinders. In addition, the oil pan bolt holes have been altered in the modified cylinder block. The holes have been chamfered to allow usage of a liquid oil pan gasket.

The “W” engine bare block will NOT be stamped with a “W”. Check for additional water galleries to identify a modified bare block. These chamfered bolt holes are also helpful in identifying the modified bare block.

The piston and pin have been changed to a full-floating type, with two snap rings to locate the piston pin. Also, piston pin outer diameter has been decreased.

The modified piston can be identified by a “W” mark on the piston skirt. NOTE: A “W” piston requires a modified connecting rod, wrist pin, and piston rings.

The modified connecting rod has been increased in weight, along with an increase in small end internal bore.

It can be identified by a “W” stamped in the side of the rod shaft as shown in illustration. NOTE: A “W” connecting rod requires a “W” piston, new style wrist pin, and modified crankshaft.

The crankshaft front tip was lengthened by 18.7 mm (0.736) in. The crankshaft pulley width was increased by 13.6 mm (0.535 in.). There are now two keys instead of just one.

Nissan made a spacer to allow you to fit the older A/B series crank pulleys to the W series cranks. The part number is 12308-V5321.

Three new water galleries were added to each cylinder head (at the exhaust side). These match the new galleries in the block.

Three new holes were added to the gasket on the exhaust side, and the six holes in the intake side of the gasket were decreased in size.

The tab shape can be used to identify the modified gasket from the non-modified gasket.